By Dr. Samarendra Pratap Singh, Professor at School of Natural Sciences, Shiv Nadar University, Delhi-NCR
In the era of a digitally connected world, the surge in consumer electronics is projected to reach unprecedented heights. It is estimated that the global and Indian consumer electronics markets are projected to reach $1.0 trillion and $92.5 billion level by 2028, respectively. This anticipated growth will be fuelled by a tremendous boost of electronic devices that have diverse functionalities for applications in the entertainment, communication, health, and information sectors. The projected trajectory of consumer electronics imposes two major practical challenges- the generation of substantial e-waste and a tremendous increase in the electricity demand.
Challenges and Environmental Impact
An explosive growth in the number of devices should be within the ambit of the sustainable development model. A recent paper published in the October 2023 issue of Nature Materials highlights that by 2030 the size of e-waste would reach ~ 74 million tons. The harmful solid e-waste majorly contains non-biodegradable toxic chemicals, metals, and semiconductor materials, and imposes serious issues on the environment.
Such a huge pile-up of e-waste, globally and in India, can lead to a man-made disaster if safe disposal is not planned and implemented. It needs attention from every stakeholder, industry, policy maker, and consumer, and demands smart strategies for ensuring a sustainable future without compromising the technological needs of individuals. On the other hand, access to electricity, with a multi-fold increase in the power supply, is also expected to affect the predicted growth of consumer electronics.
The innovative solutions to these challenges will carve viable paths leading to a sustainable and energy-efficient future. The way we produce and distribute energy, design electronic systems, use materials and processing techniques for developing electronic devices and integrated systems, and their disposal, every step needs to be reviewed, rebuilt, and practiced considering our environment.
Electronics developed using environment-friendly materials and processes are envisaged as “Green Electronics”. Conventional electronics use semiconductors, metals, and metal oxides that are processed through energy-intensive fabrication steps and are hard to recycle at the end of product life. Green electronics facilitate a transition from conventional to environment-friendly electronics using bio-degradable and earth-abundant materials, replacing hazardous materials for the fabrication of these devices. The innovation of material choices and manufacturing processes, such as additive manufacturing or printing technologies, and recycling strategies, drive academic and industrial researchers towards green electronics.
A holistic approach to green electronics is based on an integrated and balanced assessment of key aspects, like the carbon footprint of the technology, options for sustainable material, material processing and device fabrication, device performance, recycling options, and end-of-life treatments. Over the past few decades, innovations in material and device fabrication techniques have established the viability of green electronics. Organic electronics is one of the approaches that appear to offer solutions to most challenges in the realisation of green electronics.
OFETs: A basic building block of organic electronics
Most biomaterials are potential organic materials having the merits of eco- friendliness, easy availability, low cost, and low toxicity. In the past decade, organic electronics have witnessed remarkable progress in the deployment of nature-inspired and eco-friendly materials as substrates, semiconductors, and dielectrics, in organic devices. Organic field-effect transistors (OFETs), the basic elements of flexible integrated circuits, based on biomaterials have exhibited high performance.
For OFETs, edible hard gelatin, shellac, guanine, and plastics made of potato or corn starch are used as substrates, DNA, chitosan, polymeric phospholipids, silk fibroin, and various sugars are used as gate dielectrics, and beta-carotene and indigo are used as semiconductors. Most of these materials are plant/animal-derived and some can be produced from natural waste.
The charge mobility, materials property that determines operation speed, and power dissipation are the most important issues in OFETs for practical applications. The operation voltage of OFETs is larger than the same of benchmark amorphous silicon- based FETs (< 5.0 Volts). The high operation voltage produces heat, which leads to the degradation of organic materials and an undesired current in electronic circuits having a high density of OFETs.
Hence, OFETs with low voltage operation are highly desired for applications in biosensors, and flexible, wearable, and implantable electronics. Such OFETs will pave the way for energy-efficient electronic circuits powered with low-power batteries. Early-stage research establishes that applications of environment-friendly biopolymers, ionic liquids, and ion gels as the gate dielectric in OFETs lead to realising low-voltage operations.
Although challenges remain, the recent achievements in organic electronic devices
make us believe that green electronic devices are viable and will drive the future
consumer electronics market in accordance with sustainable development goals.
Organic electronic materials will not replace silicon-based electronics; however, they
will support the need-based usage of electronic devices making consumer electronics
more functional, accessible, and sustainable.